Thermostat with a solid filler, two-valve, type TC-107-01, is located in the outlet pipe of the cylinder head and is connected by hoses to the coolant pump and radiator
The main thermostat valve starts to open when the coolant temperature is 78-82°C.
At 94°C, it is already fully open.
When the main valve is closed, the liquid in the engine cooling system circulates, bypassing the radiator, through the open additional thermostat valve inside the engine cooling jacket.
When the main valve is fully open, the secondary valve is closed and all the liquid passes through the cooling radiator.
The body heater is connected in parallel with the radiator and the thermostat does not disconnect it from the engine.
Therefore, when the engine is warming up, do not open the air intake damper and turn on the heater motor.
The thermostat automatically maintains the required temperature of the coolant in the engine, turning off and on the circulation of the liquid through the radiator.
In cold weather, especially at low engine loads, almost all of the heat is removed by blowing cold air into the engine, and the coolant does not circulate through the radiator.
In order to maintain the optimal temperature regime of the engine at negative ambient temperatures, it is necessary to cover the radiator lining with a cover.
Never remove the thermostat.
In the cold season, an engine without a thermostat warms up for a long time and operates at a low coolant temperature.
As a result, its wear accelerates, fuel consumption increases, tarry substances are abundantly deposited in the engine, and normal air temperature in the car cabin is not ensured.
In the warm season, in the absence of a thermostat, most of the coolant will circulate in a small circle (through the engine cooling jacket), bypassing the radiator.
As a result, this will cause the engine to overheat.
Replacing the thermostat
On the ZMZ-406 engine
Drain the cooling system.
Disconnect the two hoses from the fittings of cover 1 of the thermostat housing.
Remove the two screws 2 and remove the cover 1.
If you need to remove the thermostat housing, you must disconnect the wires from the sensors 5, loosen the clamps 4 and unscrew the two bolts 3, remove the thermostat housing
Remove thermostat 1 from housing 2
Install the new thermostat in reverse order.
On the ZMZ-402 engine
Drain the cooling system.
Disconnect hoses 1 and 2 from the cover 6 of the thermostat housing, after loosening the clamps.
If you need to remove the thermostat housing, disconnect hose 3 and wire 4 from the coolant temperature sensor from it.
Unscrew two bolts 5 (the second bolt from the bottom of the housing) and remove the thermostat housing.
Remove the two screws 1 and remove the cover 2. Remove the thermostat 3 from the housing
Install the new thermostat in reverse order.